The invention relates generally to a protective cap for a writing, drawing or applicator implement.
For the sake of convenience in this specification, the term applicator element will be used generally to denote an implement as referred to above for writing, drawing or applying a material, on the basis that writing and drawing also involve applying material to a surface.
One form of protective cap for an applicator implement, as disclosed in JP-A-61-11 016, comprises an outer casing portion and a cap-like closure portion which is disposed in the outer casing portion and which has an insert portion for sealingly closing off an applicator member of the implement. The outer casing portion and the closure portion are connected by means of ribs which are uniformly distributed circumferentially of the cap, with openings between the ribs. In that construction the closure portion is either integrally connected to the outer casing portion or it is in the form of an independent component which is then joined to the outer casing portion. At any event the cap has through openings which are defined between the closure portion and the outer casing portion and which are separated from each other by the above-mentioned ribs. Although no reference is made in the above-indicated specification to a mould arrangement for producing the cap, which involves a particular design of sliding inserts for producing the through openings, it can be assumed that the mould arrangement will in fact include a sliding insert with fingers and with slots between the fingers for moulding the through openings in the cap. It is also to be assumed that the mould arrangement will have two sliding inserts which come to bear against each other in an obtuse position in the course of the moulding operation, due to the configuration to be formed in the moulded cap. That means that the possibility of damage to the sliding inserts or vibration in particular in respect of the fingers of the one sliding insert cannot be excluded.
Protective caps of the above-indicated design configuration in which the through openings are of a relatively large cross-sectional area of at least 5 mm.sup.2 can be designed without causing serious problems for use with applicator implements of relatively large cross-section, insofar as the cap for the implement is also of a correspondingly large cross-section. In contrast thereto however it is a very complicated matter for relatively small protective caps, that is to say caps of small cross-sectional dimensions, to be produced with through openings which are of a large cross-sectional area as referred to above. The last-mentioned implements which are of relatively small cross-section are for example pencil-slim writing, drawing or other applicator implements.
Another form of closure cap, as disclosed in GB-A-21 74 374, seeks to provide that the risk of asphyxiation in the event of the cap being swallowed is at least reduced by virtue of the closure portion being connected to the screw-on portion of the cap by means of ribs which define through openings therebetween. The ribs are disposed on the outside of the cap and extend over the entire axial length thereof. The fact that the ribs are disposed on the outside of the cap means that there is a risk of injury to the airways in the event of the cap being accidentally swallowed.
In yet another form of closure cap for writing, drawing or painting implements, as disclosed in DE 37 28 896 Cl, the cap has an insertion opening, an internal space which is open at one end, and at least one axially disposed air passage which extends along the stem or body portion of the cap. The air passage is disposed within the outside wall of the body portion of the cap and it is covered in a radially outward direction by a suitable cover configuration. The air passage is open at its ends and at least one opening thereof communicates with a recess disposed at one side of the body portion of the cap. Manufacture of that cap involves essentially the same problems as those discussed above in relation to JP-A-61-11 016, namely, regarding the movement of the sliding inserts of the moulding arrangement and the possibility of vibration thereof, which can have an adverse effect on the quality of the moulding.